Clarification 2: I, like Jeff, also have a pricing matrix for my product. Sometimes people don't read it properly and are confused - although I'm nice about it, I tend to feel unsympathetic. This is because it's hard for me to really see from someone else's point of view, since we only actually ever see from our own...
It reminds me of the founder/maintainer of a very successful programmer's website who said, "People will not read what you write [for a web-app GUI], not matter what you write, or how you write it". His frustration was maxed out. It occurred to me that one solution is to only provide buttons (i.e. actions) for what you actually want users to do. This constrains their choices to only valid ones. This amounts to a kind of "wizard" - but they've been very successful, so this isn't a bad thing. It also obeys the "don't make me think!" imperative, provided the GUI is designed-well... It also helps if the pricing options are also designed well. In fact, I believe it is worth sacrificing profit/benefit to the customer (or other efficiencies) if by doing so, you can make the choices clearer and simpler for the customer (eg. clarity can come from obvious patterns in the pricing, even if they totally don't fit the true demographics).
To apply this to successfully communicating the limits of each pricing option, where "successfully" means that the customer hears what you say, you could have a button for each limit. By consciously selecting the limit, the user would know what it is. Unfortunately, this can lead to frustrating backtracking when one choice constrains other choices in unexpected ways. One can muck around with different orderings of the choices, but I think that ultimately, the only real solution is to make the options match what the user would expect.
That is, change your pricing model to accord with what the user expects. Not vice versa. This is a kind of "pricing positioning", where the goal isn't to sell more, but to communicate better, by associating your product with a category, and then following the standard pricing approaches for that category - whether they suit you or not. The purpose is to communicate, and doing it well makes everyone happier.
For me, it's intrinsically valuable: successful communication is a joy in itself; miscommunication is suffering.